Manufacturer Description:
This legendary and sought-after Buchla synthesizer from the 200 series will be produced again after 40 years. There are some minor changes here and there but in general it´s pretty much the same as the original. UPDATE: Now playable with MIDI - Note ON, Note OFF, Aftertouch on Channel 1 which routes to the Pressure output on the 218. Most exciting is support for MIDI clock/sync messages, Pulse output at the standard 24ppqn, or if the arpeggiator is enabled will clock that... This is a really well-thought out semi-modular instrument with great sound and lots of possibilities due to well-arranged patch points. The small sequencer and the touch keyboard with integrated arpeggiator invite to play the instrument directly and to interact with it.

Technical Details

At the first glance the Easel looks confusing because of the many switches, faders and many sockets but in the end everything makes sense and it's laid out very logically. The colors of sockets mostly match the function blocks of the Easel (purple = keyboard pressure, yellow = pulser, white = random, orange = envelope, blue = sequencer). The black sockets are CV inputs that are located always left of the according parameter. The sockets at the top of the unit have legending and are self-explaining. The position of most banana sockets below the faders has been chosen for the use of shorting bridges instead of patch cords which enhances clarity of your patch.

The sound generators of the Easel are based on a complex main oscillator and a modulation oscillator. The latter is generally used for modulating the main VCO but it can act as a second VCO and it will be routed into the 2nd Lopass Gate, see below.

The main oscillator can be tuned with the frequency fader over 5 octaves and the response to incoming CV can be changed with the +/- polarity switch. The wave form is depending on the controls in the timbre section: With timbre fader and timbre potentiometer set to zero we will get a sine wave. Turning up the timbre potentiometer the waveform blends to a sawtooth, a square or a triangle, depending on the switch. The timbre fader modifies this wave form by the use of a wave multiplier for sounds with high harmonic content.

The modulation oscillator has no timbre section, only switchable waveforms (saw, square or triangle). In HI mode it's a VCO, in LOW mode it's a LFO. It's frequency can be modulated also by the keyboard (switchable) or a CV. A switch determines how the modulation oscillator affects the main oscillator, either as a ring modulator, for amplitude modulation or for frequency modulation. The modulation intensity is set with the modulation fader but can be voltage controlled, too.

The oscillator(s) are processed with the Lopass Gates (LPGs). Those are vactrol-based circuits with organic behavior and can operate as low pass filters, as VCAs (gate) or as a combination of both. The audio signal for the 1st LPG is always the main VCO. The second LPG is 180° phase shifted and has a flexible routing: either output of LPG1 (what creates high pass sounds due to the shifted phase), the modulation oscillator or an external audio signal. The outputs of the LPGs are mixed in the output section and their levels can be set separately. Behind the mixer there´s a real spring reverb with dry/wet control providing for more depth in the Easel´s sound when desired.

The Easel can be played with the touch keyboard and/or the sequencer. The keyboard senses the amount of skin touching it, resulting in a pseudo pressure sensitivity. It has a range of 2.5 octaves but you can transpose octaves with the four pads on the top right. While normal playing it senses one finger that determines the pitch, but when using the internal arpeggiator all fingers are analyzed. The arpeggiator has it´s own tempo control.

The Pulser is an impulse generator you can use as a clock source or as a second LFO. It can self-repeat or be triggered by key gate or the sequencer. The envelope is an AD or a ASR type, depending on the setting and can be triggered by the pulser, sequencer or the keyboard gate. The analog sequencer has three, four or five steps and features steps gate switches; it´s gate source can be the pulse or the keyboard gate. Interaction of the switch settings and the simultaneous keyboard play can result in really interesting rhythmical structures.

The four touch pads mentioned above can´t only transpose the octaves; in "preset" setting four pre-set fixed voltages can be played to alter the pitch or other parameters.

Memory is possible as well; you need to copy all connections and fader positions by soldering resistors etc. on the memory card. The Easel can read the values of the memory card, settings of the face plate controls or a combination of BOTH, which gives you three sounds at the same time!
inputs and outputs

Buchla Music Easel iProgram card is the ultimate accessory to modernize your Music Easel–a flexible replacement for the original resistor-based Program Cards. It makes use of the Program Card slot and enables patch editing, patch/librarian management, and even real-time performance from an iPad via the iProgram Card App. The iProgram Card communicates with the iPad via WiFi*. The iProgram card can store up to 24 presets in local flash memory so that it can be used independently from the iPad application. Two push buttons allow the user to scroll through and load any stored preset.

The iProgram Card App includes access to all sliders, knobs, patch points on the Music Easel (except output section), as well as additional routing options not available from the Easel’s front panel. The emulated 218 touch keyboard can be latched for more arpeggiation possibilities.